The World Health Organization told its member nations it was declaring a swine flu pandemic Thursday — the first global flu epidemic in 41 years — as infections climbed in the United States, Europe, Australia, South America and elsewhere.

In a statement sent to member countries, WHO said it decided to raise the pandemic warning level from phase 5 to 6 — its highest alert — after holding an emergency meeting on swine flu with its experts.

The long-awaited pandemic decision is scientific confirmation that a new flu virus has emerged and is quickly circling the globe. It will trigger drugmakers to speed up production of a swine flu vaccine and prompt governments to devote more money toward efforts to contain the virus.